Apparatus and method and computer program for generating a stereo output signal for providing additional output channels

Abstract

An apparatus for generating a stereo output signal includes a manipulation information generator being adapted to generate manipulation information depending on a first signal indication value of a first input channel and on a second signal indication value of a second input channel, and a manipulator for manipulating a combination signal based on the manipulation information to obtain a first manipulated signal as a first output channel and a second manipulated signal as a second output channel. The combination signal is a signal derived by combining the first input channel and the second input channel. Furthermore, the manipulator is configured for manipulating the combination signal in a first manner, when the first signal indication value is in a first relation to the second signal indication value, or in a different second manner, when the first signal indication value is in a different second relation to the second signal indication value.

The invention claimed is: 
     
       1. An apparatus for generating a stereo output signal comprising a first output channel and a second output channel from a stereo input signal comprising a first input channel and a second input channel comprising:
 a manipulation information generator being adapted to generate manipulation information depending on a first signal indication value of the first input channel and on a second signal indication value of the second input channel; wherein the manipulation information generator is configured to determine the manipulation information using the first signal indication value and using the second signal indication value for computing a first weighting mask; and wherein the manipulation information generator is configured to determine the manipulation information using the first signal indication value and using the second signal indication value for computing a second weighting mask, being different from the first weighting mask; and 
 a manipulator for generating the first output channel by applying the first weighting mask on a combination signal, wherein the combination signal is a signal derived by combining the first input channel and the second input channel; and 
 wherein the manipulator is configured to generate the second output channel by applying the second weighting mask on the combination signal, said combination signal being the combination signal on which the first weighting mask is applied to generate the first output channel. 
 
     
     
       2. The apparatus according to  claim 1 ,
 wherein the manipulation information generator is adapted to generate the manipulation information depending on a first energy value as the first signal indication value of the first input channel and on a second energy value as the second signal indication value of the second input channel; and 
 wherein the manipulator is configured for manipulating the combination signal in a first manner when the first energy value is in a first relation to the second energy value, or in a different second manner, when the first energy value is in a different second relation to the second energy value. 
 
     
     
       3. The apparatus according to  claim 1 ,
 wherein the manipulation information generator is adapted to generate the manipulation information depending on the first signal indication value of the first input channel and on the second signal indication value of the second input channel, 
 wherein the first signal indication value of the first input channel depends on an amplitude value of the first input channel; 
 wherein the second signal indication value of the second input channel depends on an amplitude value of the second input channel; and 
 wherein the manipulator is configured for manipulating the combination signal in a first manner when the first signal indication value is in a first relation to the second signal indication value, or in a different second manner, when the first signal indication value is in a different second relation to the second signal indication value. 
 
     
     
       4. The apparatus according to  claim 1 ,
 wherein the apparatus furthermore comprises a signal indication computing unit being adapted to calculate the first signal indication value based on the first input channel, and being furthermore adapted to calculate the second signal indication value based on the second input channel. 
 
     
     
       5. The apparatus according to  claim 1 ,
 wherein the manipulator is adapted to manipulate the combination signal, wherein the combination signal is generated according to the formula
     d ( t )= a·x   L ( t )− b·x   R ( t ),
 
 
 wherein d(t) represents the combination signal, wherein x L (t) represents the first input channel, wherein x R (t) represents the second input channel and wherein a and b are steering parameters. 
 
     
     
       6. The apparatus according to  claim 1 ,
 wherein the manipulator is adapted to manipulate the combination signal, wherein the combination signal represents a difference between the first and the second input channel. 
 
     
     
       7. The apparatus according to  claim 1 ,
 wherein the apparatus furthermore comprises a transformer unit for transforming the first and the second input channel of the stereo input signal from a time domain into a frequency domain. 
 
     
     
       8. The apparatus according to  claim 1 ,
 wherein the manipulation information generator is adapted to generate the first weighting mask depending on the first signal indication value, and to generate the second weighting mask depending on the second signal indication value; and 
 wherein the manipulator is adapted to manipulate the combination signal by applying the first weighting mask to an amplitude value of the combination signal to acquire a first modified amplitude value, and to manipulate the combination signal by applying the second weighting mask to an amplitude value of the combination signal to acquire a second modified amplitude value. 
 
     
     
       9. The apparatus according to  claim 8 ,
 wherein the apparatus furthermore comprises a combiner being adapted to combine the first modified amplitude value and a phase value of the combination signal to acquire the first manipulated signal as the first output channel; and 
 wherein the combiner is adapted to combine the second modified amplitude value and a phase value of the combination signal to acquire the second manipulated signal as the second output channel. 
 
     
     
       10. The apparatus according to  claim 8 ,
 wherein the manipulation information generator is adapted to generate the first weighting mask G L (m, k) according to the formula 
 
       
         
           
             
               
                 
                   G 
                   L 
                 
                 ⁡ 
                 
                   ( 
                   
                     m 
                     , 
                     k 
                   
                   ) 
                 
               
               = 
               
                 
                   ( 
                   
                     
                       
                         E 
                         L 
                       
                       ⁡ 
                       
                         ( 
                         
                           m 
                           , 
                           k 
                         
                         ) 
                       
                     
                     
                       
                         
                           E 
                           L 
                         
                         ⁡ 
                         
                           ( 
                           
                             m 
                             , 
                             k 
                           
                           ) 
                         
                       
                       + 
                       
                         
                           E 
                           R 
                         
                         ⁡ 
                         
                           ( 
                           
                             m 
                             , 
                             k 
                           
                           ) 
                         
                       
                     
                   
                   ) 
                 
                 α 
               
             
           
         
         or wherein the manipulation information generator is adapted to generate the second weighting mask G R (m, k) according to the formula 
       
       
         
           
             
               
                 
                   G 
                   R 
                 
                 ⁡ 
                 
                   ( 
                   
                     m 
                     , 
                     k 
                   
                   ) 
                 
               
               = 
               
                 
                   ( 
                   
                     
                       
                         E 
                         R 
                       
                       ⁡ 
                       
                         ( 
                         
                           m 
                           , 
                           k 
                         
                         ) 
                       
                     
                     
                       
                         
                           E 
                           L 
                         
                         ⁡ 
                         
                           ( 
                           
                             m 
                             , 
                             k 
                           
                           ) 
                         
                       
                       + 
                       
                         
                           E 
                           R 
                         
                         ⁡ 
                         
                           ( 
                           
                             m 
                             , 
                             k 
                           
                           ) 
                         
                       
                     
                   
                   ) 
                 
                 α 
               
             
           
         
         wherein G L (m, k) denotes the first weighting mask for a time-frequency bin (m, k), wherein G R (m,k) denotes the second weighting mask for a time-frequency bin (m,k), wherein E L (m,k) is a signal indication value of the first input channel for the time-frequency bin (m,k), wherein E R (m,k) is a signal indication value of the second input channel for the time-frequency bin (m,k) and wherein a is a tuning parameter. 
       
     
     
       11. The apparatus according to  claim 10 ,
 wherein the manipulation information generator is adapted to generate the first or the second weighting mask, wherein the tuning parameter α is α=1. 
 
     
     
       12. The apparatus according to  claim 1 ,
 wherein the apparatus comprises a transformer unit and a combination signal generator; 
 wherein the transformer unit is adapted to receive the first and the second input channel and to transform the first and second input channel from a time domain into a frequency domain to acquire a first and a second frequency domain input channel; 
 and wherein the combination signal generator is adapted to generate a combination signal based on the first and the second frequency domain input channel. 
 
     
     
       13. The apparatus according to  claim 1 ,
 wherein the apparatus further comprises a signal delay unit being adapted to delay the first input channel and/or the second input channel. 
 
     
     
       14. An upmixer for generating at least three output channels from at least two input channels comprising:
 an apparatus for generating a stereo output signal according to  claim 1  being arranged to receive two of the input channels of the upmixer as input channels; and 
 a combining unit for combining at least two of the input signals of the upmixer to provide a combination channel; 
 wherein the upmixer is adapted to output the first output channel of the apparatus for generating a stereo output signal or a signal derived from the first output channel of the apparatus for generating a stereo output signal as a first output channel of the upmixer; 
 wherein the upmixer is adapted to output the second output channel of the apparatus for generating a stereo output signal or a signal derived from the second output channel of the apparatus for generating a stereo output signal as a second output channel of the upmixer; and 
 wherein the upmixer is adapted to output the combination channel as a third output channel of the upmixer. 
 
     
     
       15. An apparatus for stereo-base widening for generating two output channels from two input channels, comprising:
 an apparatus for generating a stereo output signal according to  claim 1 , being arranged to receive the two input channels of the apparatus for stereo-base widening as input channels; and 
 a combining unit for combining at least one of the output channels of the apparatus for generating a stereo output signal with at least one of the input channels of the apparatus for stereo-base widening to provide a combination channel; 
 wherein the apparatus for stereo-base widening is adapted to output the combination channel or a signal derived from the combination channel. 
 
     
     
       16. A method for generating a stereo output signal comprising a first output channel and a second output channel from a stereo input comprising a first input channel and a second input channel comprising:
 generating manipulation information depending on a first signal indication value of the first input channel and on a second signal indication value of the second input channel; wherein determining the manipulation information is conducted using the first signal indication value and using the second signal indication value for computing a first weighting mask; and wherein determining the manipulation information is conducted using the first signal indication value and using the second signal indication value for computing a second weighting mask, being different from the first weighting mask; and 
 generating the first output channel by applying the first weighting mask on a combination signal, wherein the combination signal is a signal derived by combining the first input channel and the second input channel; and 
 generating the second output channel by applying the second weighting mask on the combination signal, said combination signal being the combination signal on which the first weighting mask is applied to generate the first output channel. 
 
     
     
       17. An apparatus for encoding manipulation information, comprising:
 a signal indication computing unit for determining a first signal indication value of a first channel of a stereo input signal and for determining a second signal indication value of a second channel of the stereo input signal; 
 a manipulation information generator being adapted to generate manipulation information depending on a first signal indication value of the first input channel and on a second signal indication value of the second input channel; 
 wherein the manipulation information generator is configured to determine the manipulation information using the first signal indication value and using the second signal indication value for computing a first weighting mask; and wherein the manipulation information generator is configured to determine the manipulation information using the first signal indication value and using the second signal indication value for computing a second weighting mask, being different from the first weighting mask; and 
 an output module for outputting the manipulation information; 
 wherein the manipulation information is suitable for generating the first output channel by applying the first weighting mask on a combination signal, wherein the combination signal is a signal derived by combining the first input channel and the second input channel; and 
 wherein the manipulation information is suitable for generating the second output channel by applying the second weighting mask on said combination signal. 
 
     
     
       18. A non-transitory computer-readable medium comprising a computer program for generating a stereo output signal comprising a first and a second output channel from a stereo input signal comprising a first input channel and a second input channel, implementing a method according to  claim 16 .